This invention relates to an apparatus for making quartz glass crucibles.
Quartz glass crucibles are used to hold molten silicon during the growing of a silicon crystal rod. Such quartz glass crucibles are manufactured by an apparatus having a rotation table which reciprocally moves between a feeding and shaping station and a heating and fusing station. As disclosed in Japanese Patent Laid-Open No. 53-45318, a pair of rotation crucibles are rotatably provided on the rotation table. A predetermined volume of grain material is fed into one of the rotation crucibles and shaped by a shaping means so as to form a shaped body therein at the feeding and shaping station, while the shaped body in the other rotation crucible is heated and fused so as to form a quartz glass crucible therein at the heating and fusing station. After that, the table rotates by 180 degrees, and the quartz glass crucible in the other rotation crucible is removed therefrom while the shaped body in the one rotation crucible is heated and fused at the heating and fusing station. Such steps are repeated.
The table and the stations are not enclosed. Thus, impurities are apt to be included in the quartz glass crucibles manufactured by the conventional apparatus. It is difficult to control the quality of the quartz glass crucibles. Also, the working atmosphere is bad because of the heat produced at the heating and fusing station.